Fiber blend, spun yarn, textile material, and method for using the textile material

ABSTRACT

The invention provides a fiber blend, spun yarn, and textile material comprising a plurality of cellulosic fibers and a plurality of first synthetic fibers. The first synthetic fibers comprise a polyoxadiazole polymer, and the polyoxadiazole polymer comprises a plurality of first repeating units and a plurality of second repeating units, the first repeating units conforming to the structure of Formula (I) below and the second repeating units conforming to the structure of Formula (II) below 
     
       
         
         
             
             
         
       
     
     Y is selected from the group consisting of chlorine, bromine, diphenylphosphine oxide, and diphenylphosphine sulfide. The invention also provides a method for protecting an individual from infrared radiation that can be generated during an electrical arc flash using such a textile material.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation-in-part of and, pursuant to 35 U.S.C.§120, claims the benefit of the filing date of co-pending U.S. patentapplication Ser. No. 13/354,842 filed on Jan. 20, 2012, whichapplication is hereby incorporated by reference in its entirety.

TECHNICAL FIELD OF THE INVENTION

The invention relates to fiber blends, spun yarns comprising such fiberblends, textile materials comprising the fibers blends and/or spunyarns, and methods for using such textile materials.

BACKGROUND

Flame resistant fabrics are useful in many applications, including theproduction of garments worn by personnel in a variety of industries oroccupations, such as the military, electrical (for arc protection),petroleum chemical manufacturing, and emergency response fields.Cellulosic or cellulosic-blend fabrics have typically been preferred forthese garments, due to the relative ease with which these fabrics may bemade flame resistant and the relative comfort of such fabrics to thewearer.

Notwithstanding the popularity of cellulosic or cellulosic-blend flameresistant fabrics, existing fabrics do suffer from limitations. Theflammability performance of many cellulosic flame resistant fabrics isnot sufficient to meet the demanding requirements of certain industries.In order to meet these requirements, inherent flame resistant fibers(e.g., meta-aramid fibers, such as NOMEX® fiber from E. I. du Pont deNemours and Company) are often employed, which increases the cost of thefabrics. Accordingly, a need remains to provide alternative flameresistant fabrics that are capable of meeting applicable flameresistance standards at lower cost.

BRIEF SUMMARY OF THE INVENTION

In a first embodiment, the invention provides a fiber blend comprising:

(a) a plurality of cellulosic fibers; and

(b) a plurality of first synthetic fibers comprising a polyoxadiazolepolymer, the polyoxadiazole polymer comprising a plurality of firstrepeating units and a plurality of second repeating units, the firstrepeating units conforming to the structure of Formula (I) below and thesecond repeating units conforming to the structure of Formula (II) below

-   -   wherein Y is selected from the group consisting of chlorine,        bromine, diphenylphosphine oxide, and diphenylphosphine sulfide;        and

wherein the cellulosic fibers and the first synthetic fibers areintimately blended.

In a second embodiment, the invention provides a spun yarn comprising:

(a) a plurality of cellulosic fibers; and

(b) a plurality of first synthetic fibers comprising a polyoxadiazolepolymer, the polyoxadiazole polymer comprising a plurality of firstrepeating units and a plurality of second repeating units, the firstrepeating units conforming to the structure of Formula (I) below and thesecond repeating units conforming to the structure of Formula (II) below

-   -   wherein Y is selected from the group consisting of chlorine,        bromine, diphenylphosphine oxide, and diphenylphosphine sulfide.

In a third embodiment, the invention provides a textile materialcomprising:

(a) a plurality of cellulosic fibers; and

(b) a plurality of first synthetic fibers comprising a polyoxadiazolepolymer, the polyoxadiazole polymer comprising a plurality of firstrepeating units and a plurality of second repeating units, the firstrepeating units conforming to the structure of Formula (I) below and thesecond repeating units conforming to the structure of Formula (II) below

-   -   wherein Y is selected from the group consisting of chlorine,        bromine, diphenylphosphine oxide, and diphenylphosphine sulfide.

In a fourth embodiment, the invention provides a method for protectingan individual from infrared radiation that can be generated during anarc flash, the method comprising the step of positioning a textilematerial between an individual and an apparatus capable of producing anarc flash, the textile material comprising:

(a) a plurality of cellulosic fibers; and

(b) a plurality of first synthetic fibers comprising a polyoxadiazolepolymer, the polyoxadiazole polymer comprising a plurality of firstrepeating units and a plurality of second repeating units, the firstrepeating units conforming to the structure of Formula (I) below and thesecond repeating units conforming to the structure of Formula (II) below

-   -   wherein Y is selected from the group consisting of chlorine,        bromine, diphenylphosphine oxide, and diphenylphosphine sulfide.

DETAILED DESCRIPTION OF THE INVENTION

In a first embodiment, the invention provides a fiber blend comprising aplurality of cellulosic fibers and a plurality of first syntheticfibers, the first synthetic fibers comprising a polyoxadiazole polymer.The fibers in the fiber blend preferably are intimately blended so thateach different fiber type is substantially evenly distributed throughoutthe fiber blend.

As noted above, the fiber blend of the invention comprises cellulosicfibers. As utilized herein, the term “cellulosic fibers” is used torefer to fibers composed of, or derived from, cellulose. Examples ofsuitable cellulosic fibers include cotton, rayon, linen, jute, hemp,cellulose acetate, and combinations, mixtures, or blends thereof. Asutilized herein, the term “rayon” refers to manufactured cellulosicfibers made from regenerated cellulose. Thus, rayon includes viscoserayon fibers (i.e., rayon fibers made by the viscose method),cuprammonium rayon fibers (i.e., rayon fibers made by the cuprammoniummethod), nitrocellulose rayon fibers (i.e., rayon fibers made by thenitrocellulose method), acetate rayon fibers (i.e., rayon fibers made bythe acetate method), and lycoell fibers. Lyocell fibers are a type ofmanufactured cellulose fiber made by dissolving wood pulp in an organicsolvent (e.g., an amine oxide solvent, such asN-methylmorphotine-N-oxide) and then extruding the solution into adilute aqueous solution of the organic solvent (e.g., the amine oxide),which precipitates the cellulose in the form of filaments. Lyocellfibers are stronger than other cellulosic fibers and retainapproximately 85% of their dry tenacity when wet. Lyocell fibers arealso inherently water absorbent, exhibiting a water absorption (or waterimbibition) of approximately 65-75%. Suitable types of rayon includeflame retardant rayon (FR rayon), which is a rayon fiber (i.e., any oneor more of the types of rayon fibers described above) having a flameretardant compound (e.g., an organophosphorous compound) incorporatedtherein. FR rayon is available from many sources, such as Lenzing AG.Preferably, the cellulosic fibers are selected from the group consistingof cotton fibers, rayon fibers (e.g., viscose rayon fibers, lyocellfibers, or a mixture thereof), and mixtures thereof. In certainembodiments, the cellulosic fibers can be a mixture of cotton fibers andrayon fibers (e.g., viscose rayon fibers, lyocell fibers, or a mixturethereof). For example, in one embodiment, the cellulosic fiberspreferably are a mixture of cotton fibers and lyocell fibers. In anotherpreferred embodiment, the cellulosic fibers comprise cotton fibers. Thecotton fibers can, as discussed below, be treated with aphosphorous-containing flame retardant.

In those embodiments comprising cotton fibers, the cotton fibers can beof any suitable variety. Generally, there are two varieties of cottonfibers that are readily available for commercial use in North America:the American Upland variety (Gossypium hirsutum) and the American Pimavariety (Gossypium barbadense). The cotton fibers used as the cellulosicfibers in the invention can be cotton fibers of either the AmericanUpland variety, the American Pima variety, or a combination, mixture, orblend of the two. Generally, cotton fibers of the American Uplandvariety, which comprise the majority of the cotton used in the apparelindustry, have lengths ranging from about 0.875 inches to about 1.3inches, while the less common fibers of the American Pima variety havelengths ranging from about 1.2 inches to about 1.6 inches. Preferably,at least some of the cotton fibers used in the invention are of theAmerican Pima variety, which are preferred due to their greater, moreuniform length.

The cellulosic fibers can be present in the fiber blend in any suitableamount. For example, the cellulosic fibers preferably can comprise about25 wt. % or more, about 30 wt. % or more, about 35 wt. % or more, orabout 40 wt. % or more of the fibers present in the fiber blend. Thecellulosic fibers preferably can comprise about 90 wt. % or less, about85 wt. % or less, about 80 wt. % or less, about 75 wt. % or less, about70 wt. % or less, about 65 wt. % or less, or about 60 wt. % or less ofthe fibers present in the fiber blend. Thus, in a preferred embodiment,the cellulosic fibers comprise about 25 wt. % to about 90 wt. % (e.g.,about 30 wt. % to about 90 wt. %, about 35 wt. % to about 90 wt. %, orabout 40 wt. % to about 90 wt. %), about 25 wt. % to about 85 wt. %(e.g., about 30 wt. % to about 85 wt. %, about 35 wt. % to about 85 wt.%, or about 40 wt. % to about 85 wt. %), about 25 wt. % to about 80 wt.% (e.g., about 30 wt. % to about 80 wt. %, about 35 wt. % to about 80wt. %, or about 40 wt. % to about 80 wt. %), about 25 wt. % to about 75wt. % (e.g., about 30 wt. % to about 75 wt. %, about 35 wt. % to about75 wt. %, or about 40 wt. % to about 75 wt. %), about 25 wt. % to about70 wt. % (e.g., about 30 wt. % to about 70 wt. %, about 35 wt. % toabout 70 wt. %, or about 40 wt. % to about 70 wt. %), about 25 wt. % toabout 65 wt. % (e.g., about 30 wt. % to about 65 wt. %, about 35 wt. %to about 65 wt. %, or about 40 wt. % to about 65 wt. %), or about 25 wt.% to about 60 wt. % (e.g., about 30 wt. % to about 60 wt. %, about 35wt. % to about 60 wt. %, or about 40 wt. % to about 60 wt. %) of thefibers present in the fiber blend. In a particularly preferredembodiment, the cellulosic fibers can comprise about 40 wt. % to about60 wt. % of the fibers present in the fiber blend.

The fiber blend comprises a plurality of first synthetic fibers, and thefirst synthetic fibers comprise a polyoxadiazole polymer. As will beunderstood by those of skill in the art, the term “oxadiazole” refers tofive-membered, heterocyclic, aromatic groups containing an oxygen atom,two nitrogen atoms, and two carbon atoms, in which at least one ofnitrogen atoms is separated from the oxygen atom by a carbon atom. Thus,there are two possible oxadiazole groups: a 1,3,4-oxadiazole group,which has the structure

and a 1,2,4-oxadiazole group, which has the structure

Thus, a polyoxadiazole polymer can comprise a 1,3,4-oxadiazole group, a1,2,4-oxadiazole group, or a mixture of the two. The polymer in thepolyoxadiazole fibers can contain any other suitable repeating group orunit, with arylene groups being particularly preferred. In a preferredembodiment, the first synthetic fibers comprise a polyoxadiazole polymerthat comprises a plurality of first repeating units and a plurality ofsecond repeating units. The first repeating units in the polyoxadiazolepolymer conform to the structure of Formula (I) below

The second repeating units in the polyoxadiazole polymer conform to thestructure of Formula (II) below

In the structure of Formula (II), Y can be any suitable group.Preferably, Y is selected from the group consisting of chlorine,bromine, diphenylphosphine oxide, and diphenylphosphine sulfide. In aparticularly preferred embodiment, Y is bromine.

The polyoxadiazole polymer can comprise any suitable amounts (e.g.,relative amounts) of the first repeating units and the second repeatingunits. Generally, the number of the first repeating units in thepolyoxadiazole polymer is greater than the number of the secondrepeating units in the polyoxadiazole polymer. For example, the ratio ofthe number of first repeating units in the polyoxadiazole polymer to thenumber of second repeating units in the polyoxadiazole polymer can beabout 5:1 or more, about 6:1 or more, about 7:1 or more, about 8:1 ormore, or about 9:1 or more. The ratio of the number of first repeatingunits in the polyoxadiazole polymer to the number of second repeatingunits in the polyoxadiazole polymer can be about 25:1 or less, about24:1 or less, about 23:1 or less, about 22:1 or less, about 21:1 orless, or about 20:1 or less. Thus, in a preferred embodiment, the ratioof the number of first repeating units in the polyoxadiazole polymer tothe number of second repeating units in the polyoxadiazole polymer isabout 5:1 to about 25:1 (e.g., about 6:1 to about 25:1, about 7:1 toabout 25:1, about 8:1 to about 25:1, or about 9:1 to about 25:1), about5:1 to about 24:1 (e.g., about 6:1 to about 24:1, about 7:1 to about24:1, about 8:1 to about 24:1, or about 9:1 to about 24:1), about 5:1 toabout 23:1 (e.g., about 6:1 to about 23:1, about 7:1 to about 23:1,about 8:1 to about 23:1, or about 9:1 to about 23:1), about 5:1 to about22:1 (e.g., about 6:1 to about 22:1, about 7:1 to about 22:1, about 8:1to about 22:1, or about 9:1 to about 22:1), about 5:1 to about 21:1(e.g., about 6:1 to about 21:1, about 7:1 to about 21:1, about 8:1 toabout 21:1, or about 9:1 to about 21:1), or about 5:1 to about 20:1(e.g., about 6:1 to about 20:1, about 7:1 to about 20:1, about 8:1 toabout 20:1, or about 9:1 to about 20:1). In one preferred embodiment,the ratio of the number of first repeating units in the polyoxadiazolepolymer to the number of second repeating units in the polyoxadiazolepolymer is from about 5:1 to about 25:1. In another preferredembodiment, the ratio of the number of first repeating units in thepolyoxadiazole polymer to the number of second repeating units in thepolyoxadiazole polymer is from about 9:1 to about 20:1.

While not wishing to be bound to any particular theory, it is believedthat the presence of the first synthetic fibers (which comprise apolyoxadiazole polymer as described above) will impart at least someflame resistant properties to the fiber blend and any materials (e.g.,spun yarns or fabrics) made therefrom. It is believed that these flameresistant properties are attributable, at least in part, to therelatively high heat stability of the polyoxadiazole polymer. Indeed, itis believed that the particular polyoxadiazole polymer described above(i.e., the polyoxadiazole polymer containing the first repeating unitsand second repeating units described above) exhibits a more desirablecombination of properties (including flame resistance) than otherpolyoxadiazole polymers (i.e., polyoxadiazole polymers that do notcomprise the described combination of repeating units). Thus, asdiscussed below, it is believed that the fiber blend of the inventionand materials made therefrom (e.g., spun yarns and fabrics) areparticularly well-suited for use in making flame resistant garments,apparel, and protective equipment.

The first synthetic fibers can be present in the fiber blend in anysuitable amount. For example, the first synthetic fibers preferably cancomprise about 5 wt. % or more, about 6 wt. % or more, about 7 wt. % ormore, about 8 wt. % or more, about 9 wt. % or more, or about 10 wt. % ormore of the fiber blend. The first synthetic fibers preferably cancomprise about 60 wt. % or less, about 55 wt. % or less, or about 50 wt.% or less of the fiber blend. Thus, in a preferred embodiment, the firstsynthetic fibers can comprise about 5 wt. % to about 60 wt. % (e.g.,about 6 wt. % to about 60 wt. %, about 7 wt. % to about 60 wt. %, about8 wt. % to about 60 wt. %, about 9 wt. % to about 60 wt. %, or about 10wt. % to about 60 wt. %), about 5 wt. % to about 55 wt. % (e.g., about 6wt. % to about 55 wt. %, about 7 wt. % to about 55 wt. %, about 8 wt. %to about 55 wt. %, about 9 wt. % to about 55 wt. %, or about 10 wt. % toabout 55 wt. %), or about 5 wt. % to about 50 wt. % (e.g., about 6 wt. %to about 50 wt. %, about 7 wt. % to about 50 wt. %, about 8 wt. % toabout 50 wt. %, about 9 wt. % to about 50 wt. %, or about 10 wt. % toabout 50 wt. %) of the fiber blend.

The fiber blend can comprise other fibers in addition to the cellulosicfibers and the first synthetic fibers. If present, these additionalfibers can be either natural fibers or synthetic fibers. Suitablesynthetic fibers include, but are not limited to, antistatic fibers(e.g., electrostatic dissipative fibers), thermoplastic syntheticfibers, and inherent flame resistant fibers. Suitable antistatic orelectrostatic dissipative fibers include, but are not limited to, carbonfibers, such as P140 antistatic carbon fibers from DuPont. Theantistatic or electrostatic dissipative fibers can be present in thefiber blend in any suitable amount. For example, the antistatic orelectrostatic dissipative fibers can comprise about 1 wt. % to about 5wt. % (e.g., about 1 wt. % to about 3 wt. %, or about 2 wt. %) of thefiber blend. The antistatic fibers have been found to be effective atmitigating electrostatic buildup that can occur in the process ofblending the fibers and also imparting antistatic properties to theyarns and textile materials (e.g., fabrics) made from the fiber blend.

Thermoplastic synthetic fibers can be included in the fiber blend toincrease the durability of textile materials (e.g., yarns and fabrics)to, for example, industrial washing conditions. In particular,thermoplastic synthetic fibers tend to be rather durable to abrasion andharsh washing conditions employed in industrial laundry facilities andtheir inclusion in, for example, a spun yarn can increase that yarnsdurability to such conditions. This increased durability of the yarn, inturn, leads to an increased durability for a textile material made fromthat yarn. Suitable thermoplastic synthetic fibers include, but are notnecessarily limited to, polyester fibers (e.g., poly(ethyleneterephthalate) fibers, poly(propylene terephthalate) fibers,poly(trimethylene terephthalate) fibers), poly(butylene terephthalate)fibers, and blends thereof), polyamide fibers (e.g., nylon 6 fibers,nylon 6,6 fibers, nylon 4,6 fibers, and nylon 12 fibers), polyvinylalcohol fibers, and combinations, mixtures, or blends thereof.

In those embodiments in which the fiber blend comprises thermoplasticsynthetic fibers, the thermoplastic synthetic fibers can be present inthe fiber blend in any suitable amount. For example, the thermoplasticsynthetic fibers can comprise about 1 wt. % or more, about 2 wt. % ormore, about 3 wt. % or more, about 4 wt. % or more, or about 5 wt. % ormore of the blend. The thermoplastic synthetic fibers can comprise about50 wt. % or less, about 45 wt. % or less, about 40 wt. % or less, about35 wt. % or less, about 30 wt. % or less, about 25 wt. % or less, about20 wt. % or less, or about 15 wt. % or less of the fiber blend. Thus, ina preferred embodiment, the thermoplastic synthetic fibers can compriseabout 1 wt. % to about 50 wt. % (e.g., about 1 wt. % to about 45 wt. %,about 1 wt. % to about 40 wt. %, about 1 wt. % to about 35 wt. %, about1 wt. % to about 30 wt. %, about 1 wt. % to about 25 wt. %, about 1 wt.% to about 20 wt. % or about 1 wt. % to about 15 wt. %), about 2 wt. %to about 50 wt. % (e.g., about 2 wt. % to about 45 wt. %, about 2 wt. %to about 40 wt. %, about 2 wt. % to about 35 wt. %, about 2 wt. % toabout 30 wt. %, about 2 wt. % to about 25 wt. %, about 2 wt. % to about20 wt. % or about 2 wt. % to about 15 wt. %), about 3 wt. % to about 50wt. % (e.g., about 3 wt. % to about 45 wt. %, about 3 wt. % to about 40wt. %, about 3 wt. % to about 35 wt. %, about 3 wt. % to about 30 wt. %,about 3 wt. % to about 25 wt. %, about 3 wt. % to about 20 wt. % orabout 3 wt. % to about 15 wt. %), about 4 wt. % to about 50 wt. % (e.g.,about 4 wt. % to about 45 wt. %, about 4 wt. % to about 40 wt. %, about4 wt. % to about 35 wt. %, about 4 wt. % to about 30 wt. %, about 4 wt.% to about 25 wt. %, about 4 wt. % to about 20 wt. % or about 4 wt. % toabout 15 wt. %), or about 5 wt. % to about 50 wt. % (e.g., about 5 wt. %to about 45 wt. %, about 5 wt. % to about 40 wt. %, about 5 wt. % toabout 35 wt. %, about 5 wt. % to about 30 wt. %, about 5 wt. % to about25 wt. %, about 5 wt. % to about 20 wt. % or about 5 wt. % to about 15wt. %) of the fiber blend. In one particularly preferred embodiment, thethermoplastic synthetic fibers comprise about 5 wt. % to about 15 wt. %of the fiber blend.

As noted above, the fiber blend can comprise inherent flame resistantfibers in addition to the cellulosic fibers and the first syntheticfibers. As utilized herein, the term “inherent flame resistant fibers”is used to refer to synthetic fibers which, due to the chemicalcomposition of the material from which they are made, exhibit flameresistance without the need for an additional flame retardant treatment.In such embodiments, the inherent flame resistant fibers can be anysuitable inherent flame resistant fibers, such as polyoxadiazole fibers(i.e., polyoxadiazole fibers comprising a polyoxadiazole polymer that isdifferent from the polyoxadiazole polymer of the first syntheticfibers), polysulfonamide fibers, poly(benzimidazole) fibers,poly(phenylenesulfide) fibers, meta-aramid fibers, para-aramid fibers,polypyridobisimidazole fibers, polybenzylthiazole fibers,polybenzyloxazole fibers, melamine-formaldehyde polymer fibers,phenol-formaldehyde polymer fibers, oxidized polyacrylonitrile fibers,partially-oxidized polyacrylonitrile fibers, modacrylic fibers,polyamide-imide fibers and combinations, mixtures, or blends thereof. Incertain embodiments, the inherent flame resistant fibers are preferablyselected from the group consisting of polyoxadiazole fibers,polysulfonamide fibers, poly(benzimidazole) fibers,poly(phenylenesulfide) fibers, meta-aramid fibers, para-aramid fibers,and combinations, mixtures, or blends thereof. In a more specificembodiment, the inherent flame resistant fibers can be selected from thegroup consisting of polyoxadiazole fibers, polysulfonamide fibers,poly(benzimidazole) fibers, para-aramid fibers, poly(phenylenesulfide)fibers, and combinations, mixtures, or blends thereof.

The inherent flame resistant fibers can be present in the fiber blend inany suitable amount. For example, the inherent flame resistant fiberscan comprise about 1 wt. % or more, about 2 wt. % or more, about 3 wt. %or more, about 4 wt. % or more, or about 5 wt. % or more of the fiberblend. The inherent flame resistant fibers can comprise about 40 wt. %or less, about 35 wt. % or less, about 30 wt. % or less, about 25 wt. %or less, about 20 wt. % or less, about 15 wt. % or less, or about 10 wt.% or less of the fiber blend. For example, in preferred embodiments, thefiber blend can further comprise about 5 wt. % to about 20 wt. % orabout 5 wt. % to about 10 wt. % of a para-aramid fiber, which isbelieved to improve the mechanical strength of the spun yarns andtextile materials (e.g., fabrics) made from the fiber blend withoutcompromising (and possibly even improving) the flame resistance of thematerials.

The fiber blend of the invention can be used to create a variety oftextile materials. For example, the fiber blend can be used alone or inconjunction with other fibers to create nonwoven textile materials. Thefiber blend can also be used to produce a spun yarn. Thus, in a secondembodiment, the invention provides a spun yarn made from the fiber blenddescribed above. In particular, the invention provides a spun yarncomprising a plurality of cellulosic fibers and a plurality of firstsynthetic fibers, the first synthetic fibers comprising a polyoxadiazolepolymer. Since the spun yarn is made using the fiber blend of theinvention, the cellulosic fibers, the first synthetic fibers, and, ifpresent, the additional fibers can be any of those described above inconnection with the fiber blend of the invention and such fibers can bepresent in the spun yarn in any of the amounts described above inconnection with the fiber blend of the invention.

The spun yarn of the invention can be made by any suitable spinningprocess. For example, the spun yarns can be formed by a ring spinningprocess, an air-jet spinning process, or an open-end spinning process.In certain embodiments, the yarns are spun using a ring spinning process(i.e., the yarns are ring spun yarns).

The fiber blend of the invention and the spun yarn of the invention caneach be used to create textile materials. For example, the spun yarn canbe used alone or in conjunction with other yarns to produce knit textilematerials (e.g., knit fabrics) or woven textile materials (e.g., wovenfabrics). Thus, in a third embodiment, the invention provides a textilematerial comprising a plurality of cellulosic fibers and a plurality offirst synthetic fibers, the first synthetic fibers comprising apolyoxadiazole polymer. Since the textile material is made using thefiber blend of the invention or the spun yarn of the invention, thecellulosic fibers, the first synthetic fibers, and, if present, theadditional fibers can be any of those described above in connection withthe fiber blend of the invention and such fibers can be present in thetextile material in any of the amounts described above in connectionwith the fiber blend of the invention.

As noted above, the textile materials of the invention can be made usingthe spun yarns of the invention in conjunction with other yarns. In suchan embodiment, these additional yarns can be any suitable type of yarn,such as monofilament yarns, multifilament yarns, spun yarns, andcombinations of such yarns, and the yarns can comprise any suitable typeof fiber, such as natural fibers, synthetic fibers, and combinations ofthe two. For example, the textile material can be formed using a firstplurality of spun yarns according to the invention and a secondplurality of spun yarns comprising, for example, cellulosic fibers aloneor in combination with thermoplastic synthetic fibers. As explainedbelow, in such an embodiment, the yarns can be disposed in a patternwisearrangement that results in one of the yarns being predominantlydisposed on one surface of the textile material and the other yarn beingpredominantly disposed on the opposite surface of the textile material.With such an arrangement, the textile material can be made in such a wayas to place the spun yarns of the invention, which will exhibit flameresistant properties due to the present of the first synthetic fibers,on a surface of the textile material where such flame resistantproperties can provide the most benefit when the textile material isworn.

The textile materials of the invention can be of any suitableconstruction. In other words, the yarns forming the textile material canbe provided in any suitable patternwise arrangement producing a fabric.Preferably, the textile materials are provided in a woven construction,such as a plain weave, basket weave, twill weave, satin weave, or sateenweave. Suitable plain weaves include, but are not limited to, ripstopweaves produced by incorporating, at regular intervals, extra yarns orreinforcement yarns in the warp, fill, or both the warp and fill of thetextile material during formation. Suitable twill weaves include bothwarp-faced and fill-faced twill weaves, such as 2/1, 3/1, 3/2, 4/1, 1/2,1/3, or 1/4 twill weaves. In certain embodiments of the invention, suchas when the textile material is formed from two or more pluralities ordifferent types of yarns, the yarns are disposed in a patternwisearrangement in which one of the yarns is predominantly disposed on onesurface of the textile material. In other words, one surface of thetextile material is predominantly formed by one yarn type. Suitablepatternwise arrangements or constructions that provide such a textilematerial include, but are not limited to, satin weaves, sateen weaves,and twill weaves in which, on a single surface of the fabric, the fillyarn floats and the warp yarn floats are of different lengths.

In one series of embodiments, the invention provides textile materialsmade from the spun yarns described above, and those textile materialscan be flame resistant. As utilized herein, the term “flame resistant”refers to a material that burns slowly or is self-extinguishing afterremoval of an external source of ignition. The flame resistance oftextile materials can be measured by any suitable test method, such asthose described in National Fire Protection Association (NFPA) 701entitled “Standard Methods of Fire Tests for Flame Propagation ofTextiles and Films,” ASTM D6413 entitled “Standard Test Method for FlameResistance of Textiles (vertical test)”, NFPA 2112 entitled “Standard onFlame Resistant Garments for Protection of Industrial Personnel AgainstFlash Fire”, ASTM F1506 entitled “The Standard Performance Specificationfor Flame Resistant Textile Materials for Wearing Apparel for Use byElectrical Workers Exposed to Momentary Electric Arc and Related ThermalHazards”, and ASTM F1930 entitled “Standard Test Method for Evaluationof Flame Resistant Clothing for Protection Against Flash FireSimulations Using an Instrumented Manikin.”

The textile material according to the invention can be treated with oneor more flame retardant treatments or finishes to render the textilematerials more flame resistant. Typically, such flame retardanttreatments or finishes are applied to a textile material containingcellulosic fibers in order to impart flame resistant properties to thecellulosic portion of the textile material. In such embodiments, theflame retardant treatment or finish can be any suitable treatment.Suitable treatments include, but are not limited to, halogenated flameretardants (e.g., brominated or chlorinated flame retardants),phosphorous-based flame retardants, antimony-based flame retardants,nitrogen-containing flame retardants, and combinations, mixtures, orblends thereof.

In one preferred embodiment, the textile material of the invention istreated with a phosphorous-based flame retardant treatment. In thisembodiment, a tetrahydroxymethyl phosphonium salt, a condensate of atetrahydroxymethyl phosphonium salt, or a mixture thereof is firstapplied to the textile material. As utilized herein, the term“tetrahydroxymethyl phosphonium salt” refers to salts containing thetetrahydroxymethyl phosphonium (THP) cation, which has the structure

including, but not limited to, the chloride, sulfate, acetate,carbonate, borate, and phosphate salts. As utilized herein, the term“condensate of a tetrahydroxymethyl phosphonium salt” (THP condensate)refers to the product obtained by reacting a tetrahydroxymethylphosphonium salt, such as those described above, with a limited amountof a cross-linking agent, such as urea, guanazole, or biguanide, toproduce a compound in which at least some of the individualtetrahydroxymethyl phosphonium cations have been linked through theirhydroxymethyl groups. The structure for such a condensate produced usingurea is set forth below

The synthesis of such condensates is described, for example, in Frank etal. (Textile Research Journal, November 1982, pages 678-693) and Franket al. (Textile Research Journal, December 1982, pages 738-750). TheseTHPS condensates are also commercially available, for example, asPYROSAN® CFR from Emerald Performance Materials.

The THP or THP condensate can be applied to the textile material in anysuitable amount. Typically, the THP salt or THP condensate is applied tothe textile material in an amount that provides at least 0.5% (e.g., atleast 1%, at least 1.5%, at least 2%, at least 2.5%, at least 3%, atleast 3.5%, at least 4%, or at least 4.5%) of elemental phosphorus basedon the weight of the untreated textile material. The THP salt or THPcondensate is also typically applied to the textile in an amount thatprovides less than 5% (e.g., less than 4.5%, less than 4%, less than3.5%, less than 3%, less than 2.5%, less than 2%, less than 1.5%, orless than 1%) of elemental phosphorus based on the weight of theuntreated textile material. Preferably, the THP salt or THP condensateis applied to the textile material in an amount that provides about 1%to about 4% (e.g., about 1% to about 3% or about 1% to about 2%) ofelemental phosphorous based on the weight of the untreated textilematerial.

Once the THP salt or THP condensate has been applied to the textilematerial, the THP salt or THP condensate is then reacted with across-linking agent. The product produced by this reaction is across-linked phosphorus-containing flame retardant polymer. Thecross-linking agent is any suitable compound that enables thecross-linking and/or curing of THP. Suitable cross-linking agentsinclude, for example, urea, a guanidine (i.e., guanidine, a saltthereof, or a guanidine derivative), guanyl urea, glycoluril, ammonia,an ammonia-formaldehyde adduct, an ammonia-acetaldehyde adduct, anammonia-butyraldehyde adduct, an ammonia-chloral adduct, glucosamine, apolyamine (e.g., polyethyleneimine, polyvinylamine, polyetherimine,polyethyleneamine, polyacrylamide, chitosan, aminopolysaccharides),glycidyl ethers, isocyanates, blocked isocyanates and combinationsthereof. Preferably, the cross-linking agent is urea or ammonia, withurea being the more preferred cross-linking agent.

The cross-linking agent can be applied to the textile material in anysuitable amount. The suitable amount of cross-linking agent varies basedon the weight of the textile material and its construction. Typically,the cross-linking agent is applied to the textile material in an amountof at least 0.1% (e.g., at least 1%, at least 2%, at least 3%, at least4%, at least 5%, at least 7%, at least 10%, at least 15%, at least 18%,or at least 20%) based on the weight of the untreated textile material.The cross-linking agent is also typically applied to the textilematerial in an amount of less than 25% (e.g., less than 20%, less than18%, less than 15%, less than 12%, less than 10%, less than 7%, lessthan 5%, less than 3%, or less than 1%) based on the weight of theuntreated textile material. In a potentially preferred embodiment, thecross-linking agent is applied to the textile material in an amount ofabout 4% to about 12% based on the weight of the untreated textilematerial. In another potentially preferred embodiment, the cross-linkingagent is applied to the textile material in an amount of about 2% toabout 7% based on the weight of the untreated textile material.

In order to accelerate the condensation reaction of the THP salt or THPcondensate and the cross-linking agent, the above-described reaction canbe carried out at elevated temperatures. The time and elevatedtemperatures used in this curing step can be any suitable combinationsof times and temperatures that result in the reaction of the THP or THPcondensate and cross-linking agent to the desired degree. The time andelevated temperatures used in this curing step can also promote theformation of covalent bonds between the cellulosic fibers and thephosphorous-containing condensation product, which is believed tocontribute to the durability of the flame retardant treatment. However,care must be taken not to use excessively high temperatures orexcessively long cure times that might result in excessive reaction ofthe flame retardant with the cellulosic fibers, which might weaken thecellulosic fibers and the textile material. Furthermore, it is believedthat the elevated temperatures used in the curing step can allow the THPsalt or THP condensate and cross-linking agent to diffuse into thecellulosic fibers where they react to form a cross-linkedphosphorus-containing flame retardant polymer within the fibers.Suitable temperatures and times for this curing step will vary dependingupon the curing oven used and the speed with which heat is transferredto the textile material, but suitable conditions can range fromtemperatures of about 149° C. (300° F.) to about 177° C. (350° F.) andtimes from about 1 minute to about 3 minutes.

In the case where ammonia is used as the cross-linking agent, it is notnecessary to use elevated temperatures for the THP salt or THPcondensate and cross-linking agent to react. In such case, the reactioncan be carried out, for example, in a gas-phase ammonia chamber atambient temperature. A suitable process for generating aphosphorous-based flame retardant using this ammonia-based process isdescribed, for example, in U.S. Pat. No. 3,900,664 (Miller), thedisclosure of which is hereby incorporated by reference.

After the THP salt or THP condensate and cross-linking agent have beencured and allowed to react to the desired degree, the resulting textilematerial can be exposed to an oxidizing agent. While not wishing to bebound to any particular theory, it is believed that this oxidizing stepconverts the phosphorous in the condensation product (i.e., thecondensation product produced by the reaction of the THP salt or THPcondensate and cross-linking agent) from a trivalent form to a morestable pentavalent form. The resulting phosphorous-containing compound(i.e., cross-linked, phosphorous-containing flame retardant polymer) isbelieved to contain a plurality of pentavalent phosphine oxide groups.In those embodiments in which urea has been used to cross-link the THPsalt or THP condensate, the phosphorous-containing compound comprisesamide linking groups covalently bonded to the pentavalent phosphineoxide groups, and it is believed that at least a portion of thephosphine oxide groups have three amide linking groups covalently bondedthereto.

The oxidizing agent used in this step can be any suitable oxidant, suchas hydrogen peroxide, sodium perborate, or sodium hypochlorite. Theamount of oxidant can vary depending on the actual materials used, buttypically the oxidizing agent is incorporated in a solution containingat least 0.1% concentration (e.g., at least 0.5%, at least 0.8, at least1%, at least 2%, or at least 3% concentration) and less than 20%concentration (e.g., less than 15%, less than 12%, less than 10%, lessthan 3%, less than 2%, or less than 1% concentration) of the oxidant.

After contacting the treated textile material with the oxidizing agent,the cured textile material preferably is contacted with a neutralizingsolution (e.g., a caustic solution with a pH of at least 8, at least pH9, at least pH 10, at least pH 11, or at least pH 12). The actualcomponents of the caustic solution can widely vary, but suitablecomponents include any strong base, such as alkalis. For example, sodiumhydroxide (soda), potassium hydroxide (potash), calcium oxide (lime), orany combination thereof can be used in the neutralizing solution. Theamount of base depends on the size of the bath and is determined by theultimately desired pH level. A suitable amount of caustic in thesolution is at least 0.1% concentration (e.g., at least 0.5%, at least0.8%, at least 1%, at least 2%, or at least 3% concentration) and isless than 10% concentration (e.g., less than 8%, less than 6%, less than5%, less than 3%, less than 2%, or less than 1% concentration). Thecontact time of the treated textile material with the caustic solutionvaries, but typically is at least 30 seconds (e.g., at least 1 min, atleast 3 min, at least 5 min, or at least 10 min). If desired, theneutralizing solution can be warmed (e.g., up to 75° C., up to 70° C.,up to 60° C., up to 50° C., up to 40° C., up to 30° C. relative to roomtemperature).

In another preferred embodiment, the textile material of the inventionis treated with a different phosphorous-containing flame retardantcompound. In this embodiment, at least a portion of the textile materialis contacted with a treatment composition to deposit the treatmentcomposition thereon. The treatment composition comprises a precondensatecompound and a cross-linking composition. The textile material is thenheated to a temperature sufficient for the precondensate compound andthe cross-linking composition to react in a condensation reaction andproduce a phosphorous-containing intermediate polymer. Then, at least aportion of the textile material having the phosphorous-containingintermediate polymer thereon is exposed to an oxidizing agent underconditions sufficient to convert at least a portion of the phosphorousatoms in the phosphorous-containing intermediate polymer to apentavalent state. The resulting phosphorous-containing polymer exhibitsflame resistant properties and imparts those properties to thecellulosic fibers in the textile material.

The treatment composition comprises a precondensate compound and across-linking composition. The precondensate compound is produced by thecondensation reaction of a reactant mixture comprising a phosphoniumcompound and a nitrogen-containing compound.

The reactant mixture can comprise any suitable phosphonium compound. Asutilized herein, the term “phosphonium compound” refers to a compoundcontaining a phosphonium cation, which is a positively chargedsubstituted phosphine. The phosphonium compound can comprise aphosphonium cation substituted with any suitable substituents, such asalkyl, haloalkyl, alkenyl, and haloalkenyl groups, all of which can besubstituted with at least one hydroxyl group. In a preferred embodiment,the reactant mixture comprises at least one phosphonium compoundconforming to the structure of Formula (X)

In the structure of Formula (X), R₁ can be any suitable group, such asan alkyl group, a haloalkyl group, an alkenyl group, or a haloalkenylgroup. In a preferred embodiment, R₁ is selected from the groupconsisting of hydrogen, C₁-C₃ alkyl, C₁-C₃ haloalkyl, C₂-C₃ alkenyl, andC₂-C₃ haloalkenyl. In another preferred embodiment, R₁ can be hydrogen.In the structure of Formula (X), X represents an anion and can be anysuitable monatomic or polyatomic anion. In a preferred embodiment, X canbe an anion selected from the group consisting of halides (e.g.,chloride), sulfate, hydrogen sulfate, phosphate, acetate, carbonate,bicarbonate, borate, and hydroxide. In another preferred embodiment, Xis a sulfate anion. In the structure of Formula (X), b represents thecharge of the anion X. Therefore, in order to provide a phosphoniumcompound that is charge neutral, the number of phosphonium cationspresent in the compound is equal to (−b). Examples of phosphoniumcompounds that are suitable for use in the reactant mixture include, butare not limited to, tetrahydroxymethyl phosphonium salts, such astetrahydroxymethyl phosphonium chloride, tetrahydroxymethyl phosphoniumsulfate, tetrahydroxymethyl phosphonium acetate, tetrahydroxymethylphosphonium carbonate, tetrahydroxymethyl phosphonium borate, andtetrahydroxymethyl phosphonium phosphate. The reactant mixture cancomprise one phosphonium compound, or the reactant mixture can comprisea mixture of two or more phosphonium compounds.

The reactant mixture can comprise any suitable nitrogen-containingcompound or combination of nitrogen-containing compounds. In a preferredembodiment, the reactant mixture comprises at least onenitrogen-containing compound conforming to the structure of Formula (XI)

In the structure of Formula (XI), R₂, R₃, R₄, R₅, R₆, and R₇ can be anysuitable groups. In a preferred embodiment, R₂, R₃, R₄, R₅, R₆, and R₇are independently selected from the group consisting of hydrogen,hydroxymethyl, and alkoxymethyl. Suitable nitrogen-containing compoundsinclude, but are not limited to, melamine, methylolated melamines, andalkoxymethyl melamines (e.g., etherified methylol melamines). Thereactant mixture can comprise one nitrogen-containing compound, or thereactant mixture can comprise a mixture of two or morenitrogen-containing compounds.

The reactant mixture can contain any suitable amounts of the phosphoniumcompound and the nitrogen-containing compound. The amounts of thephosphonium compound and the nitrogen-containing compound in thereactant mixture can be expressed through a molar ratio of the twocomponents in the reactant mixture. However, as will be understood bythose skilled in the art (and as illustrated below), it is thephosphonium cation(s) in the phosphonium compound that participate inthe reaction between the phosphonium compound and thenitrogen-containing compound. (The phosphonium compound's counterion issimply there to balance the charge.) Thus, in order to accuratelyexpress the relative amount of each reactive component present in thereactant mixture, the molar amount of the phosphonium compound presentin the reactant mixture should be normalized to express the number ofreactive phosphonium cations contributed to the reactant mixture by thephosphonium compound. This can be simply done by taking the number ofmoles of the phosphonium compound present in the reactant mixture andmultiplying this value by the number of phosphonium cations present in amolecule of the phosphonium compound. For example, if the reactantmixture contains one mole of a phosphonium compound containing twophosphonium cations per molecule (e.g., tetrahydroxymethyl phosphoniumsulfate), then the reactant mixture will contain two moles of reactivephosphonium cations ([1 mole of tetrahydroxymethyl phosphoniumsulfate]×[2 phosphonium cations per molecule of tetrahydroxymethylphosphonium sulfate]=2 moles of phosphonium cations). If two or morephosphonium compounds are present in the reactant mixture, then thiscalculation must be separately performed for each phosphonium compound.The results from each calculation can then be added to arrive at thetotal number of moles of reactive phosphonium cations present in thereactant mixture. The figure representing the number of moles ofphosphonium cations present in the reactant mixture and the molar amountof the nitrogen-containing compound can then be used to express therelative amounts of the phosphonium compound and the nitrogen-containingcompound in the reactant mixture (e.g., a molar ratio of phosphoniumcations to nitrogen-containing compound), as discussed below.

Preferably, the phosphonium compound and the nitrogen-containingcompound are present in the reactant mixture in an initial molar ratioof phosphonium cations to nitrogen-containing compound of about 50:1 orless, about 40:1 or less, about 30:1 or less, about 25:1 or less, about20:1 or less, about 15:1 or less, about 10:1 or less, or about 8:1 orless. The phosphonium compound and the nitrogen-containing compoundpreferably are present in the reactant mixture in an initial molar ratioof phosphonium cations to nitrogen-containing compound of about 3:1 ormore or about 6:1 or more. In a preferred embodiment, the phosphoniumcompound and the nitrogen-containing compound are present in thereactant mixture in an initial molar ratio of phosphonium cations tonitrogen-containing compound of about 50:1 to about 3:1. In anotherpreferred embodiment, the phosphonium compound and thenitrogen-containing compound are present in the reactant mixture in aninitial molar ratio of phosphonium cations to nitrogen-containingcompound of about 40:1 to about 3:1, about 30:1 to about 3:1, about 25:1to about 3:1, about 20:1 to about 3:1, about 15:1 to about 3:1 (e.g.,about 15:1 to about 6:1), about 10:1 to about 3:1, or about 8:1 to about3:1 (e.g., about 6:1).

The reactant mixture can contain other components in addition to thephosphonium compound and the nitrogen-containing compound describedabove. For example, the reactant mixture can contain other nitrogenouscompounds, such as urea, guanazole, biguanide, or alkylene ureas. Whilethese other nitrogenous compounds can be present in the reactantmixture, they are typically present in a relatively small amount ascompared to the amount of the nitrogen-containing compound present inthe reactant mixture. The reactant mixture can also contain asurfactant, such as an alkoxylated alcohol, which aids in the dispersionof the nitrogen-containing compound as described below. The reactantmixture can also contain one or more pH buffers, such as acetate salts(e.g., sodium acetate), phosphate salts (e.g., alkaline metal phosphatesalts), tertiary amines, and amino alcohols.

The components of the reactant mixture can be reacted under any suitableconditions which result in a condensation reaction between thephosphonium compound and the nitrogen-containing compound. In onepossible embodiment, the phosphonium compound is provided in the form ofan aqueous solution and the nitrogen-containing compound (e.g.,melamine) is provided in the form of a solid or a solid dispersed in aliquid medium. Generally, in order to facilitate the reaction betweenthe phosphonium compound and the nitrogen-containing compound, thenitrogen-containing compound is provided in the form of a solid (e.g.,powder) having relatively small particle size, such as an averageparticle size of about 100 μm or less. In this embodiment, thenitrogen-containing compound is added to the aqueous solution of thephosphonium compound while the solution is vigorously agitated. In orderto further facilitate the incorporation of the nitrogen-containingcompound in the solution, a surfactant can be added. Any suitablesurfactant can be used, such as an alkoxylated alcohol. Once thenitrogen-containing compound is added to the solution, the resultingreactant mixture is heated to a temperature sufficient to effect acondensation reaction between the phosphonium compound and thenitrogen-containing compound. In a preferred embodiment, the reactantmixture is heated to a temperature of about 60° C. to about 90° C. andmaintained within this temperature range for a sufficient amount of timefor the phosphonium compound and the nitrogen-containing compound toreact, such as about 2 hours to about 8 hours. Generally, thephosphonium compound is provided in a molar excess relative to theamount of the nitrogen-containing compound, and the reactant mixture ismaintained at the elevated temperature for a sufficient amount of timefor the nitrogen-containing compound to be completely consumed by thecondensation reaction. Since the precondensate compound formed by thereaction of the phosphonium compound and the nitrogen-containingcompound is water-soluble, the complete consumption of thenitrogen-containing compound can be visually confirmed by the absence ofsolid particles of the nitrogen-containing compound in the reactantmixture.

Although the exact chemical structure of the precondensate compound hasnot been determined, the structure of Formula (XII) below depicts oneexample of a precondensate compound that is believed to be formed by thecondensation reaction described above.

The precondensate compound depicted in the structure of Formula (XII)can be produced by reacting a tetrahydroxymethyl phosphonium salt withmelamine. For the sake of simplicity, the counterions balancing theoverall positive charge of the molecule have not been depicted. As it isdepicted in the structure of Formula (XII), the phosphonium compound(i.e., tetrahydroxymethyl phosphonium salt) was present in a sufficientamount to replace each of the six amine hydrogens present on themelamine. With such an excess of the phosphonium compound present in thereactant mixture, the resulting precondensate compound may also containoligomers (e.g., dimers, trimers, etc.) in which two or more melamine“cores” have been cross-linked by phosphonium compound molecules.Furthermore, when an excess of the phosphonium compound is used, thecondensation reaction may produce a precondensate compound that iscontained within a composition comprising a significant amount ofunreacted phosphonium compound, such as about 1% to about 50% excessphosphonium compound.

In addition to the precondensate compound described above, the treatmentcomposition comprises a cross-linking composition. The cross-linkingcomposition can comprise any suitable cross-linking compound.Preferably, the cross-linking compound comprises two nitrogen-containingfunctional groups that are capable of reacting with the hydroxyl-bearingcarbon atoms of the precondensate compound. (These hydroxyl-bearingcarbon atoms are those from the phosphonium compound that did not reactwith the nitrogen-containing compound when the precondensate compoundwas formed. An exemplary compound containing such hydroxyl-bearingcarbon atoms is depicted in the structure of Formula (XII) above.)Furthermore, each of these reactive nitrogen-containing functionalgroups preferably has only one hydrogen atom directly bonded to thenitrogen atom. Thus, when such a cross-linking compound reacts with theprecondensate compound, the nitrogen-containing functional groupsforming the cross-links will no longer have any hydrogen atoms directlybonded to the nitrogen atom of the functional group. While not wishingto be bound to any particular theory, it is believed that such across-link (i.e., a cross-link in which the nitrogen atom does not havea hydrogen atom bonded thereto) is less susceptible to oxidative attack(e.g., attack by oxidative chlorine) than a cross-link in which thenitrogen atom still bears a hydrogen atom. This reduced susceptibilityto oxidative attack is believed to contribute, at least in part, to theimproved wash durability of the flame retardant composition of theinvention.

The cross-linking composition can comprise any suitable cross-linkingcompound possessing the characteristics described above. In a preferredembodiment, the cross-linking composition comprises an alkylene ureacompound (e.g., a cyclic alkylene urea compound). In a preferredembodiment, the cross-linking composition comprises an alkylene ureacompound selected from the group consisting of ethylene urea, propyleneurea, and mixtures thereof.

The cross-linking composition can contain other compounds in addition tothe alkylene urea compound mentioned above. For example, thecross-linking composition can contain additional cross-linking agents(i.e., cross-linking agents in addition to the alkylene urea compound).Cross-linking agents suitable for such use include, for example, urea, aguanidine (i.e., guanidine, a salt thereof, or a guanidine derivative,such as cyanoguanidine), guanyl urea, glycoluril, ammonia, anammonia-formaldehyde adduct, an ammonia-acetaldehyde adduct, anammonia-butyraldehyde adduct, an ammonia-chloral adduct, glucosamine, apolyamine (e.g., polyethyleneimine, polyvinylamine, polyetherimine,polyethyleneamine, polyacrylamide, chitosan, aminopolysaccharides),glycidyl ethers, isocyanates, blocked isocyanates and combinationsthereof. While these other cross-linking agents can be present in thecross-linking composition, they typically are present in a relativelysmall amount as compared to the amount of the primary cross-linkingcompound (e.g., alkylene urea) present in the cross-linking composition.

The precondensate compound and the cross-linking composition can bepresent in the treatment composition in any suitable amounts thatpermits a condensation reaction between the two. The amounts of the twocomponents in the treatment composition can be expressed in terms of theinitial weight ratio of the two components. In a preferred embodiment,the precondensate compound and the cross-linking composition are presentin the treatment composition in an initial weight ratio of about 1:2 ormore, about 1:1 or more, about 3:2 or more, about 2:1 or more, or about3:1 or more. In another preferred embodiment, the precondensate compoundand the cross-linking composition are present in the treatmentcomposition in an initial weight ratio of precondensate compound tocross-linking composition of about 10:1 or less, about 9:1 or less,about 8:1 or less, about 7:1 or less, about 6:1 or less, about 5:1 orless, about 4:1 or less, or about 3:1 or less. Thus, in certainpreferred embodiments, the precondensate compound and the cross-linkingcomposition are present in the treatment composition in an initialweight ratio of precondensate compound to cross-linking composition ofabout 1:2 to about 10:1 (e.g., about 1:2 to about 5:1), about 1:1 toabout 10:1 (e.g., about 1:1 to about 8:1, about 1:1 to about 6:1, about1:1 to about 5:1, or about 1:1 to about 4:1), about 3:2 to about 10:1(e.g., about 3:2 to about 8:1, about 3:2 to about 4:1), or about 2:1 toabout 10:1 (e.g., about 2:1 to about 8:1, about 2:1 to about 6:1, about2:1 to about 5:1, about 2:1 to about 4:1, or about 2:1 to about 3:1).

As noted above, the cross-linking composition can contain more than onedistinct compound. For the purposes of calculating the ratios describedin the preceding paragraph, the amount of the cross-linking compositionwill be the amount (by weight) of the component(s) in the cross-linkingcomposition that are capable of reacting with the precondensate compoundin a condensation reaction. Thus, when the cross-linking compositioncontains only one compound that is capable of reacting with theprecondensate compound (e.g., an alkylene urea), then the amount used incalculating the above-described ratios will be the amount (by weight) ofthis compound (e.g., the alkylene urea) present in the cross-linkingcomposition. And, if the cross-linking composition contains more thanone compound that is capable of reacting with the precondensatecompound, the amount used for the purposes of calculating the ratiosdescribed in the preceding paragraph will be the total amount (byweight) of “reactive” compounds present in the cross-linkingcomposition. This value is simply the sum of the weight of each“reactive” compound present in the present in the cross-linkingcomposition. In either case, solvents, carriers, and other non-reactivecomponents present in the cross-linking composition are not factoredinto the calculated ratios described in the preceding paragraph.

The precondensate compound and the cross-linking composition can beprovided in any suitable form(s). For example, the precondensatecompound can be provided in the form of an aqueous solution, dispersionor suspension. Typically, the precondensate compound is provided in theform of an aqueous solution. In such an embodiment, the cross-linkingcomposition can be provided in the form of a solid that is added to theaqueous solution, or the cross-linking composition can be provided inthe form of a solution or dispersion that is mixed with the aqueoussolution.

The treatment composition can be applied to the textile material in anysuitable amount. One suitable means for expressing the amount oftreatment composition that is applied to the textile material isspecifying the amount of elemental phosphorous that is added as apercentage of the weight of the untreated textile material (i.e., thetextile material prior to the application of the treatment compositiondescribed herein). This percentage can be calculated by taking theweight of elemental phosphorous added, dividing this value by the weightof the untreated textile material, and multiplying by 100%. Typically,the treatment composition is applied to the textile material in anamount that provides about 0.5% or more (e.g., about 1% or more, about1.5% or more, about 2% or more, about 2.5% or more, about 3% or more,about 3.5% or more, about 4% or more, or about 4.5% or more) ofelemental phosphorus based on the weight of the untreated textilematerial. The treatment composition is also typically applied to thetextile material in an amount that provides about 5% or less (e.g.,about 4.5% or less, about 4% or less, about 3.5% or less, about 3% orless, about 2.5% or less, about 2% or less, about 1.5% or less, or about1% or less) of elemental phosphorus based on the weight of the untreatedtextile material. Preferably, the treatment composition is applied tothe textile material in an amount that provides about 1% to about 4%(e.g., about 1% to about 3% or about 1% to about 2%) of elementalphosphorous based on the weight of the untreated textile material.

The textile material can be contacted with the treatment compositionusing any suitable technique, such as any of the wet processingtechniques commonly used to treat textile materials. For example, thetextile substrate can be contacted with the treatment composition bypadding, foaming, or jet “dyeing” (i.e., treating the textile substratein a jet dyeing machine containing the treatment composition instead ofor in addition to a dye liquor).

In order to accelerate the condensation reaction between theprecondensate compound and the cross-linking composition, the treatedtextile material typically is heated to a temperature sufficient for theprecondensate compound and the cross-linking composition to react andproduce a phosphorous-containing intermediate polymer on the textilematerial. The time and elevated temperature used in this step can be anysuitable combination of time and temperature that results in thereaction of the precondensate compound and cross-linking composition tothe desired degree. When the textile material comprises cellulosicfibers, the time and elevated temperatures used in this step can alsopromote the formation of covalent bonds between the cellulosic fibersand the phosphorous-containing intermediate polymer produced by thecondensation reaction, which is believed to contribute to the durabilityof the flame retardant treatment. However, care must be taken not to useexcessively high temperatures or excessively long cure times that mightresult in excessive reaction of the phosphorous-containing intermediatepolymer with the cellulosic fibers, which might weaken the cellulosicfibers and the textile material. Furthermore, it is believed that theelevated temperatures used in the curing step can allow theprecondensate compound and cross-linking composition to diffuse into thecellulosic fibers where they then react to form thephosphorus-containing intermediate polymer within the cellulosic fibers.Suitable temperatures and times for this step will vary depending uponthe oven used and the speed with which heat is transferred to thetextile material, but suitable conditions can range from temperatures ofabout 149° C. (300° F.) to about 177° C. (350° F.) and times from about1 minute to about 3 minutes.

The reaction of the precondensate compound and the cross-linkingcomposition results in a phosphorous-containing intermediate polymer.Since the phosphorous-containing intermediate polymer was produced froma precondensate compound containing phosphonium cations, theintermediate polymer will contain quaternary phosphorous atoms. Thestructure depicted in Formula (XIII) below shows one possible structurefor a segment of a polymer produced by the reaction of ethylene ureawith a precondensate compound, which precondensate compound has beenmade by reacting a tetrahydroxymethyl phosphonium salt and melamine.

While such a polymer (i.e., a polymer containing quaternary phosphorousatoms) is relatively stable, it is believed that the stability and, forexample, wash durability of the polymer can be increased by convertingat least a portion of the phosphorous atoms in the polymer into apentavalent state. The structure depicted in Formula (XIV) below showsthe segment depicted in Formula (XIII) after the phosphorous atoms havebeen converted into a pentavalent state.

As can be seen from the structure depicted above, the conversion of aphosphorous atom from a quaternary state to a pentavalent involves anoxidation that converts the quaternary phosphonium group into aphosphine oxide group. This conversion (i.e., oxidation of thequaternary phosphonium groups to a pentavalent state) can be effected byreacting the phosphorous-containing intermediate polymer with a suitableoxidizing agent. Suitable oxidizing agents include, but are not limitedto, oxygen (e.g., gaseous oxygen), hydrogen peroxide, sodium perborate,sodium hypochlorite, percarbonate (e.g., alkaline metal percarbonates),ozone, peracetic acid, and mixtures or combinations thereof. Suitableoxidizing agents also include compounds that are capable of generatinghydrogen peroxide or peroxide species, which compounds can be used aloneor in combination with any of the oxidizing agents listed above. Asnoted above, the phosphorous containing intermediate polymer is exposedto the oxidizing agent for a period of time and under conditionssufficient for at least a portion of the phosphorous atoms in theintermediate polymer to be converted to a pentavalent state. In apreferred embodiment, the phosphorous containing intermediate polymer isexposed to the oxidizing agent for a period of time and under conditionssufficient to convert substantially all of the phosphorous atoms in theintermediate polymer to a pentavalent state.

After the treatment composition has been applied to the textile materialand the components of the treatment composition have been allowed toreact in the above-described condensation reaction, the resultingtextile material can be exposed to an oxidizing agent in order toconvert at least a portion of the phosphorous atoms in thephosphorous-containing intermediate polymer into a pentavalent state.The mechanism of and reasons for this conversion have been describedabove. Furthermore, oxidizing agents suitable for use in this step havealso been described above, and each of these oxidizing agents (or anysuitable combination thereof) can be used in this step of treating thetextile material.

The textile material can be exposed to the oxidizing agent using anysuitable technique. For example, the textile material can be exposed tothe oxidizing agent using any of the wet processing techniques commonlyused to treat textile materials, such as those described above inconnection with the application of the treatment composition to thetextile material. The amount of oxidizing agent used in treating thetextile material can vary depending on the actual materials used, buttypically the oxidizing agent is incorporated in a solution containingabout 0.1% or more (e.g., about 0.5% or more, about 0.8% or more, about1% or more, about 2% or more, or about 3% or more) and about 20% or less(e.g., about 15% or less, about 12% or less, about 10% or less, about 3%or less, about 2% or less, or about 1% or less), by weight, of theoxidizing agent.

After contacting the textile material with the oxidizing agent, thetreated textile material can be contacted with a neutralizing solution(e.g., a caustic solution with a pH of about 8 or more, about 9 or more,about 10 or more, about 11 or more, or about 12 or more). The actualcomponents of the caustic solution can widely vary, but suitablecomponents include any strong base, such as alkalis. For example, sodiumhydroxide (soda), potassium hydroxide (potash), calcium oxide (lime), orany combination thereof can be used in the neutralizing solution. Theamount of base depends on the size of the bath and is determined by theultimately desired pH level. A suitable amount of caustic in thesolution is about 0.1% or more (e.g., about 0.5% or more, about 0.8% ormore, about 1% or more, about 2% or more, or about 3% or more) and isabout 10% or less (e.g., about 8% or less, about 6% or less, about 5% orless, about 3% or less, about 2% or less, or about 1% or less). Thecontact time of the treated textile material with the caustic solutionvaries, but typically is about 30 seconds or more (e.g., about 1 min ormore, about 3 min or more, about 5 min or more, or about 10 min ormore). If desired, the neutralizing solution can be warmed (e.g., up toabout 75° C. greater, up to about 70° C. greater, up to about 60° C.greater, up to about 50° C. greater, up to about 40° C. greater, or upto about 30° C. greater than the ambient temperature).

Textile materials containing certain cellulosic fibers, such as cotton,viscose rayon and lyocell, were found to have little strength loss afterthe flame retardant treatments described above. These textile materialsalso exhibited wash durable retention of the flame retardant treatment.Further, textile materials comprising lyocell fibers were observed toexhibit very good softness and drape while maintaining long lastingindustrial laundry durability (e.g., 100 industrial washes).

After the treated textile material has been contacted with the oxidizingagent as described above and, if desired, contacted with a neutralizingsolution as described above, the treated textile material typically isrinsed to remove any unreacted components from the treatmentcomposition, any residual oxidizing agent, and (if the neutralizationstep was performed) any residual components from the neutralizingsolution. The treated textile material can be rinsed in any suitablemedium, provided the medium does not degrade the phosphorous-containingpolymer. Typically, the treated textile material is rinsed in water(e.g., running water) until the pH of the water is relatively neutral,such as a pH of about 6 to about 8, or about 7. After rinsing, thetreated textile material is dried using suitable textile dryingconditions.

If desired, the textile material can be treated with one or moresoftening agents (also known as “softeners”) to improve the hand of thetreated textile material. The softening agent selected for this purposeshould not have a deleterious effect on the flammability of theresultant fabric. Suitable softeners include polyolefins, alkoxylatedalcohols (e.g., ethoxylated alcohols), alkoxylated ester oils (e.g.,ethoxylated ester oils), alkoxylated fatty amines (e.g., ethoxylatedtallow amine), alkyl glycerides, alkylamines, quaternary alkylamines,halogenated waxes, halogenated esters, silicone compounds, and mixturesthereof. In a preferred embodiment, the softener is selected from thegroup consisting of cationic softeners and nonionic softeners.

The softener can be present in the textile material in any suitableamount. One suitable means for expressing the amount of treatmentcomposition that is applied to the textile material is specifying theamount of softener that is applied to the textile material as apercentage of the weight of the untreated textile material (i.e., thetextile material prior to the application of the treatment compositiondescribed herein). This percentage can be calculated by taking theweight of softener solids applied, dividing this value by the weight ofthe untreated textile material, and multiplying by 100%. Preferably, thesoftener is present in the textile material in an amount of about 0.1%or more, about 0.2% or more, or about 0.3% or more, by weight, based onthe weight of the untreated textile material. Preferably, the softeneris present in the textile material in an amount of about 10% or less,about 9% or less, about 8% or less, about 7% or less, about 6% or less,or about 5% or less, by weight, based on the weight of the untreatedtextile material. Thus, in certain preferred embodiments, the softeneris present in the textile material in an amount of about 0.1% to about10%, about 0.2% to about 9% (e.g., about 0.2% to about 8%, about 0.2% toabout 7%, about 0.2% to about 6%, or about 0.2% to about 5%), or about0.3% to about 8% (e.g., about 0.3% to about 7%, about 0.3% to about 6%,or about 0.3% to about 5%), by weight, based on the weight of theuntreated textile material.

To further enhance the textile material's hand, the textile material canoptionally be treated using one or more mechanical surface treatments. Amechanical surface treatment typically relaxes stress imparted to thefabric during curing and fabric handling, breaks up yarn bundlesstiffened during curing, and increases the tear strength of the treatedfabric. Examples of suitable mechanical surface treatments includetreatment with high-pressure streams of air or water (such as thosedescribed in U.S. Pat. No. 4,918,795, U.S. Pat. No. 5,033,143, and U.S.Pat. No. 6,546,605), treatment with steam jets, needling, particlebombardment, ice-blasting, tumbling, stone-washing, constricting througha jet orifice, and treatment with mechanical vibration, sharp bending,shear, or compression. A sanforizing process may be used instead of, orin addition to, one or more of the above processes to improve thefabric's hand and to control the fabric's shrinkage. Additionalmechanical treatments that may be used to impart softness to the treatedfabric, and which may also be followed by a sanforizing process, includenapping, napping with diamond-coated napping wire, gritless sanding,patterned sanding against an embossed surface, shot-peening,sand-blasting, brushing, impregnated brush rolls, ultrasonic agitation,sueding, engraved or patterned roll abrasion, and impacting against orwith another material, such as the same or a different fabric, abrasivesubstrates, steel wool, diamond grit rolls, tungsten carbide rolls,etched or scarred rolls, or sandpaper rolls.

The textile material of the invention can be used alone or inconjunction with other textile materials to produce garments and otherforms of protective apparel (e.g., vests, aprons, hoods, gloves, andchaps). Given the flame resistant properties imparted to the textilematerial by the inclusion of the first synthetic fibers, it is believedthat the textile material of the invention is particularly well-suitedfor use in producing apparel that is used to protect the wearer frominjury caused by exposure to fire or intense infrared radiation.

In a fourth embodiment, the invention provides a method for protectingan individual from infrared radiation that can be generated during anelectrical arc flash. In this embodiment, the method comprises the stepof positioning a textile material between an individual and an apparatuscapable of producing an electrical arc flash. The textile materialpreferably is a textile material according to the invention, such as anyembodiment of the textile material described above.

In this method embodiment of the invention, the textile material can bepositioned at any suitable point between the individual and theapparatus. However, in order to ensure that the textile material ispositioned to afford the greatest degree of protection to theindividual, the textile material preferably forms part of a garment wornby the individual. Suitable garments include, but are not limited to,shirts, pants, coats, hoods, aprons, and gloves. In a preferredembodiment, the outward-facing textile portions of a garment worn by theindividual (i.e., those portions of the garment facing towards theapparatus when the garment is being worn by the individual) consistessentially of (or even more preferably consist of) a textile materialaccording to the invention.

The method described above can be used to protect an individual from anarc flash produced by any apparatus. Typically, the apparatus is a pieceof electrical equipment. Preferably, the apparatus is capable ofproducing an arc flash having an incident energy of about 1.2calories/cm² or more (about 5 J/cm² or more) at a position at which theindividual is located. More preferably, the apparatus is capable ofproducing an arc flash having an incident energy of about 4 calories/cm²or more (about 17 J/cm² or more) at a position at which the individualis located. The apparatus preferably is capable of producing an arcflash having an incident energy of about 8 calories/cm² or more (about33 J/cm² or more) at a position at which the individual is located. Anarc flash having an incident energy such as those described above(especially an arc flash having an incident energy of about 4calories/cm² or more or about 8 calories/cm² or more) is capable ofinflicting significant injury (e.g., second degree burns) to theunprotected or under-protected skin of an individual exposed to the arcflash.

The materials of the invention (e.g., fiber blend, spun yarn, textilematerial of the invention) can be dyed to impart a desired shade to thematerial. The materials of the invention can be dyed using any suitablecolorant or combination of colorants, such as pigments, dyes, andcombinations thereof. For example, the first synthetic fibers can bedyed using cationic (basic) dyes. Applicants have found that vat dyesare particularly useful in dyeing the materials of the invention. Whilenot wishing to be bound to any particular theory, it is believed thatvat dyes are particularly useful because the vat dyes are capable ofdyeing both the cellulosic fibers and the first synthetic fibers, whichcomprise the polyoxadiazole polymer. This is surprising because vat dyestypically are not used to dye synthetic fibers. While the vat dyes canbe used and will result in dyeing of both the cellulosic fibers and thefirst synthetic fibers, the first synthetic fibers require ahigher-than-expected amount of the vat dye(s) in order to produce thedesired shade (i.e., the amount of vat dye(s) required to dye the firstsynthetic fibers a desired shade is greater than the amount required todye a similar amount of a different fiber [e.g., cotton fiber] the samedesired shade). In fact, Applicants have found that the amount of vatdye(s) needed to dye a given amount of the first synthetic fiberstypically is about twice the amount needed to dye the same amount ofcotton fibers. Thus, when a material (e.g., fiber blend, spun yarn, ortextile material) of the invention is dyed using a vat dye, the amountof vat dye(s) used should be increased accordingly, which increasedamount will depend upon the amount of the first synthetic fibers presentin the material. Applicants have also found that, by dyeing the materialwith vat dyes, the resulting color exhibits improved colorfastness tolight exposure, and the material is stabilized against degradation byultraviolet light. As noted above, the materials of the invention can bedyed with other dyes, such as disperse dyes. Typically, these dyes areused in combination with vat dyes when the material contains othersynthetic fibers, such as thermoplastic synthetic fibers (e.g.,polyester fibers or polyamide fibers).

Example 1

A 4×1 sateen fabric was woven from warp and fill yarns comprising anintimate blend of approximately 50 wt. % lyocell fibers, approximately30 wt. % first synthetic fibers comprising a polyoxadiazole polymer asdescribed above, and approximately 20 wt. % nylon 6,6 fibers. The fabricwas scoured to remove sizing, dyed with a navy vat dye in a continuousdyeing process, and treated with a phosphorous containing flameretardant according to the process described in U.S. Pat. No. 7,713,891.The treated fabric was measured to contain about 2.1% phosphorous. Thetreated fabric exhibited very good softness and drape. The fabric alsoexhibited good flame resistance when tested in accordance with ASTMD6413 entitled “Standard Test Method for Flame Resistance of Textiles(Vertical Test)” at zero washes and 100 home washes. The char length ofthe fabric tested according to ASTM D6413 after 0 wash and 100 washeswere approximately 1.2 inches (3 cm) and approximately 1.4 inches (3.6cm), respectively, both with no drip and zero second after flame.

Example 2

A 4×1 sateen fabric was woven from warp and fill yarns comprising anintimate blend of approximately 70 wt. % lyocell fibers, approximately20 wt. % first synthetic fibers comprising a polyoxadiazole polymer asdescribed above, and approximately 10 wt. % para-aramid fibers. Thefabric was scoured to remove sizing, dyed with a navy vat dye in acontinuous dyeing process, and treated with a phosphorous containingflame retardant according to the process described in U.S. Pat. No.7,713,891. The treated fabric was measured to contain about 2.2%phosphorous. The treated fabric exhibited very good softness and drape.The fabric also exhibited good flame resistance when tested inaccordance with ASTM D6413 entitled “Standard Test Method for FlameResistance of Textiles (Vertical Test).” The char length of the fabrictested according to ASTM D6413 is approximately 1.2 inches (3 cm), withno drip and zero second after flame.

Comparative Example 1

A woven fabric containing 100 wt. % lyocell fibers was treated with thesame phosphorous containing flame retardant used in Example 1. Thetreated fabric was tested in accordance with ASTM D6413 entitled“Standard Test Method for Flame Resistance of Textiles (Vertical Test).”The treated fabric had a char length of approximately 3 inches (7.6 cm).

Comparative Example 2

A fabric was woven from warp and fill yarns containing 100 wt. % of thefirst synthetic fibers used in making the fabrics in Examples 1 and 2.The fabric exhibited a weight of approximately 6 oz/yd² (200 g/m²),which was similar to the weight of the fabrics from Example 1 andExample 2. The fabric was tested in accordance with ASTM D6413 entitled“Standard Test Method for Flame Resistance of Textiles (Vertical Test).”The fabric had a char length of approximately 2.1 inches (5.3 cm).

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the subject matter of this application (especiallyin the context of the following claims) are to be construed to coverboth the singular and the plural, unless otherwise indicated herein orclearly contradicted by context. The terms “comprising,” “having,”“including,” and “containing” are to be construed as open-ended terms(i.e., meaning “including, but not limited to,”) unless otherwise noted.Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein, and eachseparate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate the subject matter of theapplication and does not pose a limitation on the scope of the subjectmatter unless otherwise claimed. No language in the specification shouldbe construed as indicating any non-claimed element as essential to thepractice of the subject matter described herein.

Preferred embodiments of the subject matter of this application aredescribed herein, including the best mode known to the inventors forcarrying out the claimed subject matter. Variations of those preferredembodiments may become apparent to those of ordinary skill in the artupon reading the foregoing description. The inventors expect skilledartisans to employ such variations as appropriate, and the inventorsintend for the subject matter described herein to be practiced otherwisethan as specifically described herein. Accordingly, this disclosureincludes all modifications and equivalents of the subject matter recitedin the claims appended hereto as permitted by applicable law. Moreover,any combination of the above-described elements in all possiblevariations thereof is encompassed by the present disclosure unlessotherwise indicated herein or otherwise clearly contradicted by context.

What is claimed is:
 1. A fiber blend comprising: (a) a plurality ofcellulosic fibers; and (b) a plurality of first synthetic fiberscomprising a polyoxadiazole polymer, the polyoxadiazole polymercomprising a plurality of first repeating units and a plurality ofsecond repeating units, the first repeating units conforming to thestructure of Formula (I) below and the second repeating units conformingto the structure of Formula (II) below

wherein Y is selected from the group consisting of chlorine, bromine,diphenylphosphine oxide, and diphenylphosphine sulfide; wherein thecellulosic fibers and the first synthetic fibers are intimately blended.2. The fiber blend of claim 1, wherein the cellulosic fibers compriseabout 40 wt. % to about 80 wt. % of the fiber blend.
 3. The fiber blendof claim 1, wherein Y is bromine.
 4. The fiber blend of claim 1, whereinthe first synthetic fibers comprise about 10 wt. % to about 50 wt. % ofthe fiber blend.
 5. The fiber blend of claim 1, wherein the ratio of thenumber of first repeating units in the polyoxadiazole polymer to thenumber of second repeating units in the polyoxadiazole polymer is fromabout 5:1 to about 25:1.
 6. The fiber blend of claim 5, wherein theratio of the number of first repeating units in the polyoxadiazolepolymer to the number of second repeating units in the polyoxadiazolepolymer is from about 9:1 to about 20:1.
 7. The fiber blend of claim 1,wherein the fiber blend comprises about 5 wt. % to about 15 wt. % of aplurality of second synthetic fibers.
 8. The fiber blend of claim 7,wherein the second synthetic fibers are selected from the groupconsisting of antistatic fibers, polyamide fibers, polyester fibers, andblends thereof.
 9. The fiber blend of claim 1, wherein the fiber blendfurther comprises a phosphorous-containing flame retardant.
 10. A spunyarn comprising: (a) a plurality of cellulosic fibers; and (b) aplurality of first synthetic fibers comprising a polyoxadiazole polymer,the polyoxadiazole polymer comprising a plurality of first repeatingunits and a plurality of second repeating units, the first repeatingunits conforming to the structure of Formula (I) below and the secondrepeating units conforming to the structure of Formula (II) below

wherein Y is selected from the group consisting of chlorine, bromine,diphenylphosphine oxide, and diphenylphosphine sulfide.
 11. The spunyarn of claim 10, wherein the cellulosic fibers comprise about 40 wt. %to about 80 wt. % of the spun yarn.
 12. The spun yarn of claim 10,wherein Y is bromine.
 13. The spun yarn of claim 10, wherein the firstsynthetic fibers comprise about 10 wt. % to about 50 wt. % of the spunyarn.
 14. The spun yarn of claim 10, wherein the ratio of the number offirst repeating units in the polyoxadiazole polymer to the number ofsecond repeating units in the polyoxadiazole polymer is from about 5:1to about 25:1.
 15. The spun yarn of claim 14, wherein the ratio of thenumber of first repeating units in the polyoxadiazole polymer to thenumber of second repeating units in the polyoxadiazole polymer is fromabout 9:1 to about 20:1.
 16. The spun yarn of claim 10, wherein the spunyarn comprises about 5 wt. % to about 15 wt. % of a plurality of secondsynthetic fibers.
 17. The spun yarn of claim 16, wherein the secondsynthetic fibers are selected from the group consisting of antistaticfibers, polyamide fibers, polyester fibers, and blends thereof.
 18. Thespun yarn of claim 10, wherein the spun yarn further comprises aphosphorous-containing flame retardant.
 19. The spun yarn of claim 10,wherein the spun yarn further comprises a vat dye, and the vat dye isdeposited on both the cellulosic fibers and the first synthetic fibers.20. A textile material comprising: (a) a plurality of cellulosic fibers;and (b) a plurality of first synthetic fibers comprising apolyoxadiazole polymer, the polyoxadiazole polymer comprising aplurality of first repeating units and a plurality of second repeatingunits, the first repeating units conforming to the structure of Formula(I) below and the second repeating units conforming to the structure ofFormula (II) below

wherein Y is selected from the group consisting of chlorine, bromine,diphenylphosphine oxide, and diphenylphosphine sulfide.
 21. The textilematerial of claim 20, wherein the cellulosic fibers comprise about 40wt. % to about 80 wt. % of the textile material.
 22. The textilematerial of claim 20, wherein Y is bromine.
 23. The textile material ofclaim 20, wherein the first synthetic fibers comprise about 10 wt. % toabout 50 wt. % of the textile material.
 24. The textile material ofclaim 20, wherein the ratio of the number of first repeating units inthe polyoxadiazole polymer to the number of second repeating units inthe polyoxadiazole polymer is from about 5:1 to about 25:1.
 25. Thetextile material of claim 24, wherein the ratio of the number of firstrepeating units in the polyoxadiazole polymer to the number of secondrepeating units in the polyoxadiazole polymer is from about 9:1 to about20:1.
 26. The textile material of claim 20, wherein the textile materialcomprises about 5 wt. % to about 15 wt. % of a plurality of secondsynthetic fibers.
 27. The textile material of claim 26, wherein thesecond synthetic fibers are selected from the group consisting ofantistatic fibers, polyamide fibers, polyester fibers, and blendsthereof.
 28. The textile material of claim 20, wherein the textilematerial further comprises a phosphorous-containing flame retardant. 29.The textile material of claim 20, wherein the textile material furthercomprises a vat dye, and the vat dye is deposited on both the cellulosicfibers and the first synthetic fibers.
 30. A method for protecting anindividual from infrared radiation that can be generated during an arcflash, the method comprising the step of positioning a textile materialbetween an individual and an apparatus capable of producing an arcflash, the textile material comprising: (a) a plurality of cellulosicfibers; and (b) a plurality of first synthetic fibers comprising apolyoxadiazole polymer, the polyoxadiazole polymer comprising aplurality of first repeating units and a plurality of second repeatingunits, the first repeating units conforming to the structure of Formula(I) below and the second repeating units conforming to the structure ofFormula (II) below

wherein Y is selected from the group consisting of chlorine, bromine,diphenylphosphine oxide, and diphenylphosphine sulfide.
 31. The methodof claim 30, wherein the textile material is part of a garment worn bythe individual.
 32. The method of claim 30, wherein the cellulosicfibers comprise about 40 wt. % to about 80 wt. % of the textilematerial.
 33. The method of claim 30, wherein Y is bromine.
 34. Themethod of claim 30, wherein the first synthetic fibers comprise about 10wt. % to about 50 wt. % of the textile material.
 35. The method of claim30, wherein the ratio of the number of first repeating units in thepolyoxadiazole polymer to the number of second repeating units in thepolyoxadiazole polymer is from about 5:1 to about 25:1.
 36. The methodof claim 35, wherein the ratio of the number of first repeating units inthe polyoxadiazole polymer to the number of second repeating units inthe polyoxadiazole polymer is from about 9:1 to about 20:1.
 37. Themethod of claim 30, wherein the textile material comprises about 5 wt. %to about 15 wt. % of a plurality of second synthetic fibers.
 38. Themethod of claim 37, wherein the second synthetic fibers are selectedfrom the group consisting of antistatic fibers, polyamide fibers,polyester fibers, and blends thereof.
 39. The method of claim 30,wherein the textile material further comprises a phosphorous-containingflame retardant.
 40. The method of claim 20, wherein the textilematerial further comprises a vat dye, and the vat dye is deposited onboth the cellulosic fibers and the first synthetic fibers.